What's Hot: Slim for a battery case, functions very well as a security device, and easy to use.

What's Not: The alarm can go off within 20 feet even in long range setting.

Kensington makes great security accessories for notebooks, and now they've applied their security expertise to their iPhone accessories. The Kensington BungeeAir Security Case with built-in battery for the iPhone 4/4S works like an electronic leash and an external battery case. It comes with a free app that gives you security features that integrate with iOS to provide alarms, password protections and more while keeping your iPhone 4S nearby. The Kensington BungeeAir achieves these all wirelessly.

Design

The Kensington BungeeAir Security Battery Case for the iPhone 4 and iPhone 4S comes in a fitted case. Slide your iPhone 4S into the 30-pin connector dock on the bottom of the case, and install the front cover that locks on the bottom, you've got a battery case that can charge and sync your iPhone. The two-piece case design makes it easy to put it on and take it off of the iPhone 4. The BungeeAir case has a built-in 1500mAh Lithium Polymer battery and weighs only 2.6 ounces. Since the battery isn't super high in capacity, the case doesn't add too much bulk to the iPhone 4/4S. As with many battery cases, the BungeeAir case is sturdy and very protective of the iPhone 4S.

To work with BungeeAir's security features, the battery case comes with a fob keychain that beeps and vibrates when the alarm goes off. You can hang your house keys or car keys on the keychain so that you can keep the fob with you at all times. The BungeeAir key fob has two buttons (one for sound control and the other for vibration control) and a speaker grill on the front. There is a power on/off slider on the side that you need a ball pen tip or a pointy object to slide as it's inset of the housing a bit to avoid accidental sliding. The key fob comes with two coin cell batteries.

Security Features

The most useful security feature the Kensington BungeeAir provides is to remind you not to leave your iPhone 4S behind. First you put the phone in the BungeeAir case, then download the BungeeAir app on the iTunes App Store, and finally turn on the key fob. Now your BungeeAir security is turned on. If you walk away from your phone, the fob will start to beep and vibrate to let you know that you are away from your iPhone 4S. The BungeeAir app uses the iPhone's passcode protection, and you must turn on the passcode protection to use the BungeeAir security features. When you walk away from your phone, the BungeeAir fob communicates with the iPhone 4 and lock the phone with passcode protection while alerting you. So even if you are too slow to get back to your phone, your data is protected by the passcode. Will you be too late to get to your phone? Not likely. The key fob will beep at about 20 feet between the fob and your iPhone 4S, unless you don't hear it or feel the vibration or staying at a thief's den, you will likely be able to get your phone back. In fact, this electronic leash effectively ensures that you take your phone with you all the time. We tested the feature in a large house and couldn't leave the phone in one room while going into another before the fob started beeping.

The Kensington BungeeAir offers another feature: you can use your iPhone 4S to find the key fob on the other end of the electronic leash. So if you do use the key fob as your house/office/car keychain, you can use the BungeeAir app on your iPhone to find the keychain when you misplace it. Touch the button that says "Find my key" on the screen, your keychain will beep and vibrate.

Battery Case Features

The Kensington BungeeAir Battery case for iPhone 4/4S also charges the phone and has data pass through so that you can sync it while charging the battery. The battery can charge the iPhone 4 for at least one full charge from 0% to 100%, but it doesn't have rapid charging. It will take at least a couple of hours to dump the full battery capacity to the iPhone, so it's a good case to keep on your phone throughout the day and charge the battery when you need it. The case has an essential feature as an effective battery case, a power button on the back just below the LED indicator for battery levels. You can turn on the battery charging when you need it and turn it off when you don't to save battery life on the case.

Unlike some battery cases that you would use mostly for charging, then go back to your usual case for protection, the Kensington BungeeAir is designed for you to use it as the primary case when you are traveling or visiting coffee shops. The case is very functional with a cutout for the top mic and audio jack, side cutout for the silence button that fits all iPhone 4 models and a rear camera cutout for the lens and flash. The case has a built-in 30-pin connector dock that charges the iPhone 4S with the built-in battery, and allows it to sync when connected to the computer via microUSB port on the case. It also comes with an USB/microUSB cable. The front of the case has two sound holes for the bottom mic and speaker, and they work pretty well at letting sound in and out from the iPhone.

The back of the Kensington BungeeAir has the built-in battery as well as a thin cutout. The case comes with a credit sized card stand, and you can slide the card into the thin cutout to stand the iPhone 4S in landscape mode. The card stand looks flimsy but it's actually pretty effective and steady at holding up the iPhone. It's not designed to prop up your iPhone in portrait mode.

Conclusion

The Kensington BungeeAir battery case packs a lot of features into a small package. The case is form fitting and doesn't add too much bulk. It's convenient to top off your iPhone 4S' battery or gives you a full charge on a long flight. But the most useful function is to make sure you don't leave your iPhone 4 or iPhone 4S behind in your hotel room, a bar or a coffee house; and lock the phone with passcode protection via its Wireless Security Tether.